Stop motion for knitting machines



Nov. 15, 1949 c. s. MARTIN ET AL 3 STOP-MOTION FOR KNITTING MACHINES Filed Nov. 6, 1945 5 Shee'ts-She'ec l CKLW $1M Mag 2 J5, lA/VEA/TQQJ' Nov. 15, 1949 c. s. MARTlN".E! AL s'roP-mo'non FOR KNITTING MACHINES 5 Sheets-Sheet 2 Filed Nov. 6, 1945 Nov. 15, 1949 c. s. MARTIN ETAL 2,438,133 I STOP-MOTION FOR KNITTING MACHINES Filed NOV. 6, 1945 5 Sheets-Sheet 3 ccvveea gaff Z1 3 Nov. 15, 1949 c. s. MARTiN ETAL 2,438,133

STOP-MOTION FOR KNITTING MACHINES Filed Nov; 6, 1945 5 Sheets-Sheet 4 xt r Nov. 15, 1949 c. s'. MARTIN ET AL I 2,488,133

STOP-MOTION FOR KNITTING ma mas Filed Nov. 6, 1945 I 5 Sheets-Sheet 5 FIG. 9.

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)3 M & Swine)! Patented Nov. 15, 1949 STOP MOTION FOR KNITTING MACHINES Charles Stanley Martin, Leicester, Lewis Henry Golton, WestBridgford, Nottingham, and Albert Edward Cooke, Leicester, England Application November 6, 1945-, Serial No. 629,207" In Great Britain November 11,1944

18 Claims. (01. 66-463) The present invention concerns the. stop motion, of knitting machines, particularly but not exclusively Cottons patent and other straight bar knitting machines wherein at least one yarn carrier travels to and fro along a line. of needles.

It may here be explained that the expression "stopmotion is employed herein in the same broad sense that it is used in the trade to include not only a motion (i. e. mechanism or apparatus). whereby the machine is actually brought to rest but also a motion whereby the knitting opera tions or certain thereof are suspended.

As. viewed from one aspect. the invention provides in a knitting machine incorporating a yarn carrier travelling to and fro along a line of needles, a stopmotion functioning automatically at the end of the carrier traverse in the event of ab.-- normal thread supply conditions such, as thread supply failure and/ or thread slacknessr As viewed from another aspect the invention provides in a kmtting machine incorporating a yarn carrier which; travels along a line of needlesa stop-motion including a yarn detector which travels. with the carrier.

The invention also includes a stop motion of a knitting machine incorporating a yarn carrier travelling to and fro along a line of needles, having a thread detector for placing a strain on, the yarn at the end of the carrier traverse. Preferably the detector operates by exercising pressure on the yarn transversely to. its length, and the arrangement may be such that if the yarn is absent or if it is unduly slack the detector is permitted to make an additional movement which operates electric contacts. The invention further provides in a. knitting machine incorporating a yarn carrier for feeding yarn, to the needles, a stop motion including a yarn detector mounted on the. carrier.

The foregoing and. other features of the invention set out in the appended claims are incorporated' in the constructions which will now be described with reference to the accompanying drawings in which-- Figure 1 is a side elevation of a stop motion incorporating a detector as aforesaid;

Figure 2 is a perspective view of the detector;

Figure 3 is a view thereof with the cover removed;

Figure 4 is a wiring diagram of the stop motion circuit; a

Figure 5 is a cross section through the relevant parts of a Cottons patent. or other straight bar knitting machine incorporating the invention and showing one means. by which the. needle bar is 2. thrown out of action on operation of the stop motion;

Figure 6 is a view of adetail thereof;

Figure 7 shows a yarn carrier incorporating a detector, while 7 a Figure 8 is a perspective view oi this detector;

Figure 9 is a circuit diagram illustrating a modification.

The drawings illustrate the application of the invention to a. Cottons patent or other straight bar knitting machine having a representative carrier 1 which travels toand fro along a line of needles 2 with an amplitude of travel which is determined by adjustable end stops in known manner; for example the carrier may be mounted on a rod 3 (such as is shown in Figs. 1 and 7) which itself travels between the. stops. The carrier l makes one travel for each knitting, cycle of the machine so that each cycle results in the production of a course of knitted stitches.

According to one embodiment of the invention the yarn T- travels to the carrier l through a stationary detector 4 which operates at each end of the carrier traverse to test the yarn for continuity and for correct tension. This detector comprises a feeler 5 pivoted at 6 and having a yarn-guiding eye I at its lower end. Normally this: feeler 5 rests against an adjustablestop 8-. but when the carrier comes to either end of its traverse thefeeler is momentarily biased or swung sideways towards the contact 9. If the thread T is present and correct the said thread resists this movement and terminates it short of the contact 9. On the other hand if the thread is absent or if it is unduly slack the movement will continue until the contact Ed on the feeler 5 strikes thecontact 9 to complete an electric circuit which brings the stop motion into operation.

The momentary impulse or bias given to the feeler 5 exercises a momentary tug on the yarn T tending to pull it back from the, tube Ia at the extremity of the carrier I:. From this it follows that the; occurrence of a slub or the like on the yarn will, if said slub sticks in the tub la of the carrier I, the tension of the. yarn at the supply side of the carrier tube will be retained with the result that the detector will givev a false response.

For example, when a slub sticks in the carrier eye it may cause a rupture of the yarn at the needles or between. the eye and the. needles, but because of the sticking slubthe slight tug given to the yarn at: the supply side of the.- eye will not reveal this breakage. In, order to avoid this difficulty it is preferred that the yarn T shall run through a slub catcher in which. is located. at

the supply side of the feeler. This slub catcher may consist of a small bore tube.

In the example shown in Figs. 1, 2, and 3, the representative feeler is biased or impulsed to apply a momentary stress on the yarn each time the carrier I comes to a standstill, by means of an electro-magnet I I which when energised attracts the armature I 2 and by means of a hook I3 pulls the feeler 5 sideways. The wiring diagram is shown in Fig. 4 wherein I4 indicates a supply transformer and IS the stop-and-start switch for the motor driving the machine. The electromagnet l I of the detector 4 is supplied by way of a switch I6 operable by a cam I? on a shaft I8- such for example as the main cam shaft of the machine, so that the electro-magnet is energised once at each end of the traverse i. e. once in each knitting cycle of the machine. 5, completing a circuit with contact 9 an electromagnet I9 is energised to attract an armature pawl 20. This brings the stop motion into operation. It will be appreciated that the timing of cam l1 fixes the timing of the detector impulse in relation to the occurrence of the pressing motions of the machine and that the timing of the start and finish of the carrier travel varies in relation to the pressing motions according to whether wide or narrow fabric is being knitted. If the cam is so fixed on the cam shaft that the detector 5 is given an impulse after the carrier comes to a standstill in the case of narrow fabric, the same cam timing will result, when the same machine comes to knit wide fabric, in the detector being given an impulse and the yarn test being made somewhat before the carrier comes to a standstill. It will therefore be appreciated that references herein to operation of the detector at the end of the carrier traverse are to be construed in a broad sense.

It will be appreciated that although each division of a multi-division machine has several carriers, only one carrier is shown in the drawings as a representative example together with its Upon the feeler.

the press lever 24, which latter is connected to a lever 25 depending from the needle bar by a hand lever 26 provided when a recess 21 for the reception of a stud 28 on the press lever 24. This arrangement ensures that when the hand lever 26 is lifted to disengage it from the stud 28 the pressing motion of the machine is interrupted. According to the present invention the stop motion produces this disengagement automatically. For this purpose there is a lever 29 pivoted intermediate its ends on the stud 28 and carrying at its front end a stud 39 which is located beneath the front end of hand lever 26. Therefore, if the -rear end of lever 29 is forced down the stud 30 lifts the hand lever 26 and raises the recess 21 from the stud 28.

In order to pull down the rear end of lever 29 the latter is connected by a flexible connection 3|, (such for example as a cable) to a spring operated wind-up drum 32 having a key 33 by which it may be wound-up to accumulate the necessary energy. Normally the drum 32 is prevented from rotating to Wind-up the cable 3| by means of the pawl 20 engaging a tooth 34 on it, but the momentary energisation of the electromagnet I9 releases the pawl 20 and permits the drum 32 to make a revolution. Upon the resultant disengagement of hand lever 26 from lever 24 the needle bar is swung away from the presser 2| by associated detector 4. Each carrier is provided with a detector, and all the detectors are preferably gathered together into a unitary piece of apparatus which may conveniently be positioned on the head of the machine and provided with a tell-tale light which, being illuminated, shows that the stop motion has operated in the associated section. The several detectors will be connected in parallel in the circuit to a common electro-magnetic device I9. They may all be con nected by way of a common timing switch I6. The primary features of such an arrangement are illustrated in Fig. 9, which shows a series of carriers I each with its own detector unit 4a4d, said detectors being grouped in a unitary piece of apparatus indicated by dotted lines 4A. The electromagnets I I of all these units are connected by leads exemplified at a, 4512, etc., with the supply unit I4 while the contacts 6, 1 of all detector units 4a, 42), etc., are connected in parallel (by leads 46) in the circuit controlling electromagnetic device I9. This circuit also controls the tell-tale 4'! through holding relay 48.

The stop motion preferably operates to throw the needle bar 2a away from the presser 2| so that the needles are prevented from pressing, and one example of mechanism by which this may be efiected is illustrated in Figures 5 and 6. As is known, in a Cottons patent knitting machine the pressing motions of the needle bar 2a are effected by means of a cam (indicated at 22) on the main cam shaft l8 acting on a truck 23 on the spring indicated at 35. In this position the needles are incapable of pressing. Therefore, the detection of a fault by the detector 4 results in the knitting operations of the needle bar or knitting section of the machine being suspended and a press-off is prevented.

The drum 32 is re-set, when the hand lever 26' is pulled rearwards manually and is forced down to re-engage the recess 21 with stub 28.

In general it will be found preferable in a multidivision machine to provide mechanism as hereinbefore described with reference to Fig. 5 for each division so that if a fault is detected in one division, knitting is suspended on that division only while the other divisions continue in activity. Alternatively or in addition the detection of a fault in any division may serve to stop the motor of the machine through the switch I5, Fig. 4.

In the alternative construction of detector shown in Figs. 7 and 8 the detector 36 is carried by the carrier I and it comprises a small cantilever spring 31, the free end of which engages and is positioned by the running yarn. This free end carries a movable contact38 and is located be-' tween two spaced stationary contacts 39, 40 on the carrier. These three contacts constitute 'a detector controlling the stop motion, their function being to detect a yarn breakage or failure in the yarn supply or an undue slackness in the yarn, and tobring the stop motion into operation when the carrier I reaches one end of its traverse or draw.

It will be understood that the carrier is brought rapidly to a standstill at the end of the draw, for example by the impact of the rod 3 on' a stop. This rapid deceleration produces a tendency for the movable contact to swing laterally of the yarn T towards one or other of the stationary contacts according to the direction of draw. That is to say, instead of the springor feeler being momentarily biased to make a yarn-stressing movement by electro-magnetic means, it is biased by inertia means. The tendency to swing is normally resisted by the yarn if present and at the correct tension (the yarn being momentarily stressed) while if the yarn is absent, or if its tension is too low, the feeler makes an additional movement, contactis made and the stop-motion operates.

It is desirable however, to provide means for gripping the yarn at the supply side of the detector contacts at the moment of impact, For this purpose the thread in its passage to the detector contacts may travel between two inertia members 4!, 42 which are carried by the carrier or rod. The impact urges one of said members towards the other so that the thread is gripped between them, and. the detector therefore operates, if the thread is present and correct, on the length which extends fromthis gripping devicethe eye 1. In a knitting machine incorporating; a yarn carrier which travels to and fro along a. line of needles; a stop motion including a detector for initiating its functioning and for testing the presence and correct tensionin of the yarn, and means for causing the detector to place a testing strain on the yarn only at an end of the carrier traverse.

2. In a knitting machine incorporating a yarn carrier which travels to and fro along a line of needles; a stop motion including a detector for engaging the yarn before the latter reaches the needles and for responding to abnormality in the yarn conditions thereby to cause the stop motion to operate, and means for causing the detector to submit the yarn to a momentary testing strain at the end of the carrier traverse.

3. In a knitting machine incorporating a yarn carrier which travels to and fro along a line of needles; a stop motion, including a detector for placing a strain on the yarn only at the end of the carrier traverse, and means for biasing the detector to make a yarn-stressing movement at the end of said traverse.

4. In a knitting machine incorporating a line of needles and a yarn carrier which travels to and fro along that line; a stop motion including a yarn detector for placing a strain on the yarn at the end of the carrier traverse, means for biasing the detector to make a yarn-stressin movement at the end of the traverse, and means responsive to the extent of said movement for bringing the stop motion into operation.

5. Apparatus according to claim 4, having electro-magnetic means for imparting the bias to the detector.

6. Apparatus according to claim 4, havin inertia-means for imparting the bias to the detector,

'7. In a knitting machine incorporating a traversing yarn carrier for feeding yarn to the needles, a stop motion comprising a detector traversing with the carrier for momentarily stressing the yarn to test for its presence and correct tension and for responding to abnormal conditions to bring the stop motion into operation to suspend knitting operations.

8. In a knitting machine incorporating a yarn carrier travelling to and fro along a line of needles; a stop motion including a detector controlling its operation, and means for rendering the detector operative at the end of the carrier traverse to test the yarn at a location before it reaches the needles for abnormalities in yarn conditions, which means includes an electric circuit associated with the detector and a timing switch for timing the test.

9. In a straight bar knitting machine having a line of needles and'a carrier movableto and fro along it; a stop motion for preventing apressofi in the event of abnormal thread conditions, which stop'motion includes ayarn detector for engaging the yarn before it reaches the needles, means for momentarily biasing the detector at the end of the carrier traverse to make a movement resisted by the yarn if present and correct; and means operable by an excessive movement of the detector to bring the stop motion intoop eration.

10. In a knitting machine having a line of needles and a feeder, traversing to and fro along said line for feeding thread thereto, testing means for momentarily testing the thread, at a location before it reaches the needles, for continuity' andcorrect tension, means controlled by said testing means for preventing a press-offin the event of thread breakage or undue slackness, and timing means for causing the testing means to operate periodically in successive knitting cycles of the machine.

11, For a Cottons patent knitting machine having a yarn carrier movable to and fro along a line of needles, a stop motion for preventing a press-off in the event of yarn breakage or undue slackness, including a detector for testing the yarn momentarily for continuity and tension, and timing means for causing the testing means to operate at the end of the carrier traverse.

12. Apparatus according to claim 9 for a machine incorporating a plurality of carriers, having a detector for each carrier and having said detectors grouped in a unit.

13. In a knitting machine incorporating a line of needles and a yarn carrier which travels to and fro along that line; a stop motion including a yarn detector for placing a strain on the yarn at the end of the carrier traverse, and means gripping the yarn at the supply side of the detector while the latter places a strain on the yarn.

14. In a knitting machine incorporating a line of needles and a yarn carrier which travels to and fro along that line; a stop motion including a yarn detector for placing a strain on the yarn at the end of the carrier traverse and inertiaoperated yarn-gripping means for gripping the yarn at the supply side of the detector while the latter exercises the said strain.

15. In a knittin machine incorporating a line of bearded needles and a yarn carrier travelling to'and fro along the line, a stop motion functioning automatically at the end of the carrier traverse in the event of abnormal thread supply conditions which stop motion incorporates means for preventing the needles from pressing.

16. In a straight bar knitting machine having a line of needles and a carrier movable to and fro along it; a stop motion for preventing a press-01f in the event of abnormal thread conditions, which stop motion includes a yarn detector for engaging the yarn before it reaches the needles, means for momentarily biasing the detector to make a movement resisted by the yarn is present and correct, and means operable by excessive movement of the detector to bring the stop motion into operation at the end of a carrier traverse to prevent a press-off.

1'7. In a straight bar knitting machine having a line of needles and a carrier movable to and fro along the line to feed yarn thereto, said machine performing a recurrent knitting cycle resulting in successively knitted courses being cast oil the needles, each cycle including a carrier traverse; a stop motion for preventing a pressofi at the end of a cycle in the event of abnormal thread conditions, which stop motion comprises a yarn detector for engaging the yarn before it reaches the needles, means for momentarily biasing the detector at each cycle to make a movement resisted by the yarn if present and correct, and means operable by an excessive movement of the detector to bring the stop motion into operation at the end of the carrier traverse.

18. In a knitting machine incorporating a yarn carrier travelling to and fro along a line of needles, one traverse in each knitting cycle of the machine; a stop motion for preventin a press-ofi" in the event of abnormal thread conditions, which stop motion includes a yarn detector for operating on the yarn before the latter reaches the needles and for detecting abnormal thread conditions, means operable by response or the detector to bring the stop motion into operation at an end of the carrier traverse to prevent a press-oft, and means for rendering the detector momentarily operative at each knitting cycle, which means comprises an electric cir- 5 cuit associated with the detector, a timing switch in the circuit, and means acting in each cycle to operate the switch.

CHARLES STANLEY MARTIN. LEWIS HENRY COLTON. 10 ALBERT EDWARD COOKE.

REFERENCES CITED The following references are of record in the file of this patent:

15 UNITED STATES PATENTS Number Name Date 379,832 Talcott, 2nd. Mar. 20, 1888 1,718,835 Rolston June 25, 1929 20 2,050,389 Simpson Aug. 11, 1936 2,265,100 Colton Dec. 2, 1941 

